ps.sh

#!/bin/sh
PAGESIZE=`getconf PAGESIZE`;
TOTAL_MEMORY=`cat /proc/meminfo | head -n 1 | awk '{print $2}'`;

# Mimic the output of ps -ax -o pid=,ppid=,pcpu=,pmem=,command=
# Read all numeric subdirectories in /proc
for pid in `cd /proc && ls -d [0-9]*`
	do {
		if [ -e /proc/$pid/stat ]
		then
			echo $pid;

			# ppid is the word at index 4 in the stat file for the process
			awk '{print $4}' /proc/$pid/stat;

			# pcpu - calculation will be done later, this is a placeholder value
			echo "0.0"

			# pmem - ratio of the process's working set size to total memory.
			# use the page size to convert to bytes, total memory is in KB
			# multiplied by 100 to get percentage, extra 10 to be able to move
			# the decimal over by one place
			RESIDENT_SET_SIZE=`awk '{print $24}' /proc/$pid/stat`;
			PERCENT_MEMORY=$(((1000 * $PAGESIZE * $RESIDENT_SET_SIZE) / ($TOTAL_MEMORY * 1024)));
			if [ $PERCENT_MEMORY -lt 10 ]
			then
				# replace the last character with 0. the last character
				echo $PERCENT_MEMORY | sed 's/.$/0.&/'; #pmem
			else
				# insert . before the last character
				echo $PERCENT_MEMORY | sed 's/.$/.&/';
			fi

			# cmdline
			xargs -0 < /proc/$pid/cmdline;
		fi
	} | tr "\n" "\t"; # Replace newlines with tab so that all info for a process is shown on one line
	echo; # But add new lines between processes
done